Apparatus for adjusting seats in motor vehicles

ABSTRACT

Apparatus for adjusting a seat in a motor vehicle forwardly or backwards has guide rails on the floor of the passenger compartment in the vehicle, seat supporting rails which are movable along the guide rails, toothed racks on the guide rails, pinions meshing with the racks, and a motor-driven transmission with a rotary output element which serves to rotate the pinions in order to move the supporting rails along the guide rails. The shaft which transmits torque to the pinions has an external gear in mesh with an internally toothed portion of an axially movable sleeve which is further provided with an externally toothed portion movable into and from mesh with an internal gear of the output element. A shifting element is provided to move the sleeve axially into and from mesh with the internal gear of the output element. This enables the occupant of the seat or another person to disengage the output element from the shaft in the event of failure of the motor and to permit non-motorical adjustment of the position of the seat. A spring is provided to permanently bias the shifting element to a position in which the output element can transmit torque to the pinions.

BACKGROUND OF THE INVENTION

The invention relates to adjusting apparatus in general, and moreparticularly to improvements in apparatus which can be used withadvantage for forward and rearward adjustment of seats in vehicles, forexample, of the driver's seat or of the seat next to the driver's seatin a motor vehicle.

It is known to install a seat in a motor vehicle in such a way that theentire seat can be shifted forwardly or backwards for convenience of ashort- or long-legged driver or passenger and/or to provide more roomfor the legs of the occupant or occupants of a rear seat. As a rule, thefloor of the passenger compartment is provided with a pair ofspaced-apart guide rails which extend in the longitudinal direction ofthe vehicle and serve to support and guide second rails which areprovided at the underside of the body-supporting portion of the seat.One set of rails is provided with toothed racks and the other set ofrails supports pinions which mate with the adjacent racks and areconnected to each other by a transversely extending torque-transmittingshaft. The shaft can be rotated by the output element of a motor-driventransmission. The motor and transmission are connected with those railswhich carry the pinions and their shaft.

An adjusting apparatus of the above outlined character is disclosed, forexample, in German Offenlegungsschrift No. 27 47 592 of Kluting. Theapparatus of Kluting employs a slip clutch which is interposed betweenthe output element of the transmission and the shaft for the pinionswhich mate with the toothed racks. The slip clutch is designed in such away that it is capable of transmitting torque from the output element ofthe transmission to the shaft for the pinions under normal circumstancesbut permits the output element to rotate relative to the shaft when theforward or rearward movement of the seat is impeded e.g., by an objectin front of or behind the forwardly and rearwardly adjustable seat or bythe legs of the occupant or occupants of the seat or seats behind theadjustable seat. Moreover, the torque which the slip clutch can transmitis selected with a view to ensure that the rearwardly moving seat cannotinjure an occupant of the seat behind the adjustable seat, i.e.,rearward movement of the adjustable seat is interrupted or prevented ifthe rear part of the seat reaches the leg or legs of a person sittingbehind the adjustable seat.

A drawback of the adjusting apparatus of Kluting is that the seat cannotbe adjusted at all, or only in response to exertion of a substantialeffort, if the motor fails or is out of commission for another reason. Aperson attempting to shift the seat forwardly or backwards is thenrequired to overcome the resistance which the slip clutch offers torotation of the common shaft for the pinions. This can present problems,especially to a person occupying the adjustable seat.

German Offenlegungsschrift No. 27 33 484 to Wirtz et al. discloses aseat adjusting apparatus wherein the motor which is used to bring abouta change of inclination of the back rest of a seat in a motor vehiclecan be detached from the inclination changing mechanism. A screw must berotated to disengage a clutch disc which normally transmits torquebetween a common pintle for pivotable leaves forming part of hingeswhich connect the pivotable back rest to the body supporting portion ofthe seat and a gear which can be driven by the motor and is rotatable onthe shaft. The screw must be rotated by a suitable tool to move theclutch disc axially of the shaft and the screw is rotatably mounted inthe shaft. Manipulation of the screw by a screwdriver or a like tool ispossible or convenient only when a person wishing to detach the motorfrom the shaft does not occupy the seat. Moreover, such person is likelyto disengage the screw from the shaft instead of disengaging the motorfrom the shaft. Still further, the motor cannot be used to move the seatforwardly or backwards.

OBJECTS OF THE INVENTION

An object of the invention is to provide a novel and improved apparatuswhich can be used to adjust a part or device, such as the seat in amotor vehicle, either by way of a motor or by hand or legs with theexertion of a relatively small effort.

Another object of the invention is to provide the apparatus with noveland improved means for disengaging the motor from the seat displacingmechanism.

A further object of the invention is to provide a novel and improvedtorque-transmitting connection between one or more pinions and amotor-driven transmission in he above outlined apparatus.

An additional object of the invention is to provide a motor vehiclewhich embodies one or more apparatus of the above outlined character.

Still another object of the invention is to provide an apparatus whereinthe motor can be disconnected from the pinion or pinions in a simple andtime-saving manner and with the exertion of a minimal effort.

A further object of the invention is to provide an apparatus wherein themotor can be completely disengaged from the pinion or pinions so thatthe position of a seat or another part can be changed without the needto overcome the resistance of the motor to such change.

Another object of the invention is to provide an apparatus wherein themeans for attaching the motor to or for detaching the motor from one ormore pinions can be used as a device for locking the manually adjustedobject in the newly selected position.

SUMMARY OF THE INVENTION

The invention is embodied in a motion transmitting apparatus,particularly in an apparatus which can be used to move a seat forwardlyand backwards. Such seats can be used with advantage in motor vehicles.

The improved apparatus comprises at least one stationary guide memberwhich defines an elongated path, at least one mobile supporting memberwhich is adjacent the guide member and is movable along the path,displacing means including at least one toothed rack provided on one ofthe members (preferably on the guide member) and at least one pinionmating with the rack and rotatably journalled in or on the other member,drive means associated (e.g., movable) with the other member and havinga rotary output element, and means for releasably coupling the outputelement to the pinion. The coupling means comprises a mobile couplingelement and means for moving the coupling element between a firstposition in which the coupling element establishes a torque-transmittingconnection between the output element of the drive means and the pinion,and a second position in which the torque-transmitting connection isinterrupted.

The guide member can comprise a fixed rail which can be secured to thefloor in the passenger compartment of a motor vehicle, and thesupporting member can include a second rail which carries the seat inthe passenger compartment of the vehicle. The pinion has a shaft and theoutput element has an axial hole. The coupling element preferablycomprises a sleeve which is extends into the hole of the output elementand surrounds the shaft, at least in the first position of the couplingelement. The output element of the drive means in such apparatus ispreferably provided with an internal gear in the hole, and the shaft hasan external gear. The sleeve has an externally toothed portion whichmeshes with the internal gear of the output element in the firstposition of the coupling element, and the sleeve further comprises aninternally toothed portion which meshes with the gear of the shaft inthe first position of the coupling element. At least one of the twotoothed portions of the sleeve is out of mesh with the respective gearin the second position of the coupling element.

The hole of the output element can constitute a through hole or bore.The drive means can include a motor and a transmission which is drivenby the motor and includes the output element. The latter can berotatably mounted in the case or housing of the transmission.

In accordance with a presently preferred embodiment, the guide membercomprises two fixed parallel first rails and the supporting membercomprises two parallel second rails each of which is adjacent andmovable along one of the first rails. The displacing means thenpreferably comprises a toothed rack on each rail of the one member and apinion rotatably mounted on each rail of the other member and matingwith the adjacent rack. Such apparatus can further comprise atorque-transmitting element which operates between the two pinions. Thetorque transmitting element can include or constitute a second shaftwhich is coaxial with the shaft of the at least one pinion and isdrivingly connected to the other pinion. One of these shafts has aninternal gear and the other shaft has an external gear in mesh with theinternal gear. The arrangement is preferably such that the external gearis provided on the shaft of the one pinion, and such external gearmeshes with the internally toothed portion of the sleeve, at least inthe first position of the coupling element.

The sleeve can further include a bearing (e.g., in the form of a shortcylinder) which extends into the hole of the output element at least inthe second position of the coupling element.

The sleeve is movable axially between the first and second positions,and the means for moving the coupling element includes means for movingthe sleeve axially. The sleeve includes a portion which is locatedexternally of the output element in each position of the couplingelement and is provided with an external groove. The moving means forsuch sleeve can include an entraining portion (e.g., a fork) whichextends into the groove. The moving means further comprises a shiftingelement which is movably (e.g., turnably) mounted on the other memberand has a handgrip portion movable between a first positioncorresponding to the first position of the coupling element and a secondposition corresponding to the second position of the coupling element.Still further, the apparatus can comprise means for yieldably biasingthe shifting element to its first position in which the sleeve of thecoupling element is ready to rotate the one pinion in response tostarting of the motor of the drive means. The biasing means can includeat least one spring, particularly a torsion spring which reacts againstthe other member and bears against the shifting element to turn thelatter to a position corresponding to the first position of the couplingelement. At least a portion of the torsion spring can surround theshifting element.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved apparatus itself, however, both as to its construction and itsmode of operation, together with additional features and advantagesthereof, will be best understood upon perusal of the following detaileddescription of certain specific embodiments with reference to theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

The single Figure of the drawing is a fragmentary partially plan andpartially horizontal sectional view of an apparatus which embodies oneform of the invention and can be used to move a seat forwardly orbackwards, the coupling element being shown in a position in which thedrive means is ready to rotate two coaxial pinions in order to move theseat forwardly or rearwardly.

DESCRIPTION OF PREFERRED EMBODIMENTS

The drawing shows an apparatus which can be used to move a seat (notshown) in a motor vehicle forwardly or backwards. Seats which can bemoved by the apparatus of the present invention are disclosed, forexample, in commonly owned U.S. Pat. No. 4,786,110 to Mahling et al. andin commonly owned U.S. Pat. No. 4,804,226 to Schmale. The improvedapparatus comprises a guide member 10 which can be secured to the floorin the passenger compartment of a motor vehicle and includes two spacedapart parallel guide rails 11 extending in the longitudinal direction ofthe vehicle. A seat supporting member of the apparatus comprises tworails 12 each of which is adjacent one of the rails 11 and is guided bythe respective rail 11 for movement along an elongated path extending inparallelism with the rails 11. The manner in which the supporting rails12 can be fixedly secured to the underside of the body supportingportion of a seat in a motor vehicle forms no part of the presentinvention.

The means for displacing the rails 12 relative to the rails 11 comprisestwo elongated toothed racks 13 which are affixed to or form integralparts of the guide rails 11 and are parallel to all of the rails, andtwo coaxial pinions 14 each of which mates with one of the racks 13 andwhich are rotatably mounted in or on the respective supporting rails 12.The left-hand pinion 14 of the illustrated apparatus has a shaft 15which extends toward the other pinion 14 and includes an external gear16. The term gear is used herein in its broadest sense and is intendedto embrace splined shafts and like rotary parts capable of receivingtorque from or of transmitting torque to coaxial parts which are movableaxially of the gears or vice versa. The gear 16 can have one or moreaxially parallel teeth (e.g., in the form of keys which alternate withsplines) so that it can mesh with an internal gear which hascomplementary teeth (e.g., in the form of keys alternating withsplines).

The gear 16 extends into the internal gear of a hollow torquetransmitting shaft 22 which drives the shaft 15' of the right-handpinion 14. In addition, the gear 16 extends with clearance through anaxial through hole or bore 17 in an output element 18 which is rotatablein the case 35 of a transmission 20 on the left-hand rail 12. The case35 is separably affixed to the adjacent rail 12 by one or more units 36on bolts 37 which are welded to the rail 12 and extend through the case35.

The transmission 20 forms part of a drive for the pinions 14, and suchdrive further includes a reversible electric or other suitable motor 19which is affixed to the case 35 and can be started in a desireddirection by the occupant of the seat which is mounted on the supportingrails 12 in a manner not forming part of the invention. The outputelement of the motor 19 drives the input element of the transmission 20to thereby rotate the output element 18 in a desired direction. Theoutput element 18 has an internal gear 24 which surrounds the hole 17and normally meshes with an externally toothed portion 23 of asleeve-like coupling element 21 (hereinafter called sleeve) whichextends into the hole 17 and a portion of which projects from the outputelement 18 toward the left-hand pinion 14. Such portion of the sleeve 21is formed with an annular external groove 26.

The sleeve 21 forms part of a mechanism which serves to separably couplethe gear 16 on the shaft 15 of the left-hand pinion 14 to the driveincluding the motor 19 and its transmission 20. Such mechanism furthercomprises means for moving the sleeve 21 axially between the illustratedfirst position in which the sleeve establishes a torque-transmittingconnection between the output element 18 and the shaft 15, and a secondposition in which the output element 18 can rotate with reference to thegear 16 and vice versa. The moving means comprises a turnable shiftingelement 27 having a fork 28 at one end and a handgrip element 29 at theother end. The fork 28 extends into the groove 26 and constitutes ameans for displacing the sleeve 21 in response to turning of theshifting element 27 by way of the handgrip element 29 between a firstposition (shown in the drawing) corresponding to the first axialposition of the sleeve 21 and a second position which corresponds to thesecond axial position of the sleeve. The shifting element 27 is turnablein brackets 33 which are welded to the adjacent supporting rail 12.

The apparatus further comprises means for yieldably biasing the shiftingelement 27 to its first position (in which the sleeve 21 transmits orcan transmit torque between the output element 18 and the shaft 15) tothus ensure that the motor 19 is disengaged from the shafts 15, 22 and15' only as long as the handgrip element 29 is grasped by hand tomaintain the shifting element 27 in the second position. The illustratedbiasing means comprises a stressed torsion spring 30 which surrounds aportion of the shifting element 27 and has a first leg 31 reactingagainst the adjacent rail 12 and a second leg 32 bearing against thehandgrip element 29 and tending to turn the shifting element 27 from theposition which is shown in the drawing.

The sleeve 21 has an internally toothed portion 38 which is in permanentmesh with the gear 16 of the shaft 15. The sleeve 21 further comprises acylindrical bearing 25 which is surrounded by the output element 18 andon which the output element rotates when the sleeve 21 is moved to itssecond axial position in which the output element 18 can rotate relativeto the pinions 14 and vice versa. The outer diameter of the bearing 25equals or closely approximates the diameter of the hole 17 in the outputelement 18.

The reference character 34 denotes a mechanism which is used to move thesupporting rails 12 up and down in order to raise or lower the bodysupporting portion of the seat. The details of the mechanism 34 form nopart of the present invention.

If the occupant of the seat or another person wishes to adjust the rails12 forwardly or backwards, the controls for the motor 19 are actuated inthe desired direction so that the output element 18 of the transmission20 rotates the sleeve 21 which, in turn, rotates the gear 16 of theshaft 15. The shaft 15 then directly drives the left-hand pinion 14 andindirectly drives the right-hand pinion 14 through the medium of theshafts 22 and 15'. The pinions 14 roll along the respective toothedracks 13 and move the supporting rails 12 in the desired direction. Thetorsion spring 30 maintains the shifting element 27 in that angularposition in which the externally toothed portion 23 of the sleeve 21meshes with the internal gear 24 of the output element 18 and theinternally toothed portion 38 of the sleeve 21 meshes with the gear 16of the shaft 15.

If the motor 19 is out of commission or is not capable of rotating theoutput element 18 for any other reason, the seat on the supporting rails12 can be shifted forwardly or backwards in response to turning of theshifting element 27 to its second position against the resistance of thetorsion spring 30. The fork 28 then displaces the sleeve 21 so that thelatter assumes its second position in which at least one of its toothedportions 23, 38 is out of mesh with the respective gear 24, 16. At thesame time, the bearing 25 ensures that the orientation of the shaft 15remains unchanged, i.e., the shaft 15 remains in that position in whichit is coaxial with the shafts 22 and 15'. In the illustrated apparatusthe internally toothed portion 38 of the sleeve 21 is in permanent meshwith the gear 16 of the shaft 15 but the externally threaded portion 23is out of mesh with the internal gear 24 of the output element 18 whenthe sleeve 21 is moved to its second position in response to turning ofthe shifting element 27 against the resistance of the torsion spring 30.

When the movement of the sleeve 21 to its second position is completed,the occupant of the seat on the supporting rails 12 can plant her or hisfeet against the floor prior to pushing or pulling the seat and therails 12 forwardly or backwards, i.e., along the paths which are definedby the floor-mounted guide rails 11. When the adjustment withoutassistance from the motor 19 is completed, the handgrip element 29 issimply released to enable the torsion spring 30 to turn the shiftingelement 27 to the illustrated angular position, i.e., the sleeve 21returns into mesh with the output element 18 to thereby hold the seat inthe newly selected position. The transmission 19 can include orconstitute a self-locking worm gear transmission which acts as a meansfor reliably holding the seat in the manually or pedally(non-motorically) selected position.

An advantage of the improved apparatus is that the drive including themotor 19 and transmission 20 offers no resistance to adjustment of thesupporting rails 12 relative to the guide rails 11 when the couplingincluding the sleeve 21 is actuated to disconnect the motor 19 from thepinions 14. Moreover, the motor 19 and transmission 20 can serve as ameans for locking the supporting rails 12 in positions which areselected without assistance from the motor. All a person wishing tosecure the seat in the newly selected position has to do is to releasethe handgrip element 29 so that the torsion spring 30 is free to returnthe externally toothed portion 23 of the sleeve 21 into mesh with theinternal gear 24 of the output element 18.

Another advantage of the improved apparatus is its simplicity. Thus, aperson desiring to adjust the supporting rails 12 relative to the guiderails 11 When the motor 19 is out of commission, or cannot be used forsuch adjustment for any other reason, need not employ any tools and/orpossess any technical skills because the adjustment is extremely simpleand takes up little time. All that is necessary is to temporarily movethe sleeve 21 out of mesh with the output element 18 of the drive forthe pinions 14. The apparatus is ready for motorical adjustment of theposition of supporting rails 12 relative to the guide rails 11 as soonas the non-motorical adjustment is completed, i.e., the person occupyingthe seat on the rails 12 or another person knows that it is possible touse the motor 19 as a means for adjusting the position of the seat untiland unless the handgrip element 29 is caused to turn the shiftingelement 27 from the position which is shown in the drawing.

The improved apparatus is susceptible of many modifications withoutdeparting from the spirit of the invention. For example, the illustratedturnable shifting element 27 can be replaced with an electromagnet, witha pusher or with any other suitable means for shifting the sleeve 21between its first and second positions.

It is further possible to provide the toothed racks 13 on the supportingrails 12 and to mount the pinions 14 and the drive means including themotor 19 and transmission 20 on the floor next to one of the guide rails11. However, the illustrated mounting of toothed racks 13 on the guiderails 11 is preferred at this time because the shifting element 27 thenshares the movements of the supporting rails 12. This ensures that aperson occupying the seat on the supporting rails 12 can immediatelylocate the handgrip element 29 because the (axial) position of theshifting element 27 relative to the seat cannot be changed.

It is also possible to provide the right-hand end portion of the shaft15 with internal teeth and to provide the left-hand end portion of thetorque transmitting shaft 22 with external teeth mating with theinternal teeth of the shaft 15.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic and specific aspects of our contributionto the art and, therefore, such adaptations should are intended to becomprehended within the meaning and range of equivalence of the appendedclaims.

We claim:
 1. Motion transmitting apparatus, particularly for moving forwardly and backwards a seat in a vehicle, comprising at least one stationary guide member defining an elongated path; at least one mobile supporting member adjacent said guide member and movable along said path; displacing means including at least one toothed rack provided on one of said members and extending longitudinally of said path and at least one pinion mating with said rack and rotatably carried by the other of said members, said pinion having a shaft; drive means associated with said other member and including a motor and a transmission driven by said motor, said transmission having a rotary output element and said output element having an axial through hole; and means for releasably coupling said output element to said pinion, said coupling means comprising a mobile coupling element and means for moving said coupling element between a first position in which said coupling element establishes a torque-transmitting connection between said output element and said pinion and a second position in which said connection is interrupted, said coupling element including a sleeve extending into said hole and surrounding said shaft.
 2. The apparatus of claim 1, wherein said guide member comprises a fixed rail and said supporting member includes a second rail.
 3. The apparatus of claim 1, wherein said output element has an internal gear in said hole and said shaft has an external gear, said sleeve having an externally toothed portion which meshes with said internal gear in the first position of said coupling element and an internally toothed portion which meshes with said external gear in the first position of said coupling element, at least one of said toothed portions being out of mesh with the respective gear in the second position of said coupling element.
 4. The apparatus of claim 1, wherein said transmission has a case and said output element is rotatably mounted in said case.
 5. The apparatus of claim 1, wherein said guide member includes tow first rails and said supporting member includes two second rails each adjacent and movable along one of said first rails, said displacing means comprising a toothed rack on each rail of said one member and a pinion for each of said racks, and further comprising a torque-transmitting element between said pinions, said torque-transmitting element having a second shaft which is coaxial with the shaft of said at least one pinion, one of said shafts having an internal gear and the other of said shafts having an external gear mating with said internal gear.
 6. The apparatus of claim 5, wherein said external teeth are provided on the shaft of said at least one pinion and said sleeve has an internally toothed portion meshing with said external gear in the first position of said coupling element and an externally toothed portion meshing with an internal gear of said output element in the first position of said coupling element, at least one of said toothed portions being out of mesh with the respective gear in the second position of said coupling element.
 7. The apparatus of claim 1, wherein said sleeve has an externally threaded portion meshing with an internal gear of said output element and an internally threaded portion, said shaft including an external gear meshing with said internally threaded portion in the first position of said coupling element, said sleeve further including a bearing which extends into said output element at least in the second position of said coupling element.
 8. The apparatus of claim 1, wherein said bearing includes a cylinder.
 9. The apparatus of claim 1, wherein said is movable axially between said first and second positions, said moving means including means for moving said sleeve axially between said first and second positions.
 10. The apparatus of claim 9, wherein said sleeve includes a portion which is located externally of said output element in each position of said coupling element and has an external groove, said moving means including an entraining portion which extends into said groove.
 11. The apparatus of claim 10, wherein said moving means further comprises a shifting element movably mounted on said other member and having a handgrip portion movable between a first position corresponding to the first position of said coupling element and a second position corresponding to the second position of said coupling element.
 12. The apparatus of claim 11, wherein said entraining portion includes a fork.
 13. The apparatus of claim 11, further comprising means for yieldably biasing said shifting element to the first position thereof.
 14. The apparatus of claim 13, wherein said shifting element is turnable between said first and second positions thereof and said biasing means includes a torsion spring which reacts against said other member and bears against said shifting element.
 15. The apparatus of claim 14, wherein a portion of said torsion spring surrounds said shifting element.
 16. The apparatus of claim 1, wherein said guide member is fixed and said toothed rack is provided on said guide member. 